Continuous inductive train-control system



. July 9, 1929. w HAILES 1.720.631

CONTINUOUS INDUCTIVE TRAIN CONTROL SYSTEM Filed June 22, 1925 3 Sheets-Sheet 1 :9 I 7 k l I Q. l

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y 9, 1929- w. D. HAILES 1.720.631

CONTINUOUS INDUCTIVE TRAIN CONTROL SYSTEM Filed June 22, 1925 a Sheets-Sheet 2 M15235; P wwiiwl FIG. 2

July 9, 1929. w. D. HAILES CONTINUOUS INDUCTIVE TRAIN CONTROL SYSTEM Filed June 22, 1925 3 Sheets-Sheet FIGS.

aw/ MM A ATTORNEK Patented July 9, 1929.

UNITED STATES 1,720,631 PATENT OFFICE.

WILLIAM D. HAILES, OF ROCHESTER, NEW YORK, ASSIGNOR TO GENERAL RAILWAY SIGNAL COMPANY, OF ROCHESTER, NEW YORK.

CONTINUOUS INDUCTIVE TRAIN-CONTROL SYSTEM.

Application filed June 22, 1925. Serial No. 38,752.

This invention relates to an automatic train control system, and more particularly concerns a train control system of thQ'COH- tinuous inductive type employing alternating currents in the track rails to inductively control electro-responsive means on a moving vehicle.

It is often found desirable in connection with train control systems to provide such a system of control as will cause the engineer to keep on the alert and to observe and recognize traflic conditions ahead by suitably acknowledging each unfavorable indication of the wayside signals by a suitable manual act; this vigilance on the part of the engineer being encouraged by the provision of a suitable penalty, such as an automatic brake application bringing the train to a stop or materially reducing its speed, if such acknowledging act is not performed. In this manner, the protection afforded by the automatic control means is combined with the usual physical control of the engineer, and train operation is doubly safeguarded.

Although the engineer may properly recognize and acknowledge unfavorable traflic conditions as indicated by the wayside signals, he may, for various reasons, be tempted to increase the train speed to a value greater than that required for safe train operation under the existing traffic conditions. For this reason, it is desirable to provide some means of imposing an automatic brake application if a safe speed under given traflic conditions is exceeded, which application may be re leased as soon as the speed has been reduced to a safe value.

In combining a control system of the type described with the continuous inductive method of influence transmission, it is found that delays in train operation are often occasioned by the fact that the alternating control currents, flowing in the track rails, are interrupted at switches, crossovers and like points, and that these interruptions in the control currents cause an operation of the car-carried apparatus which simulates a change to more unfavorable traffic conditions. Obviously, the engineer cannot recognize and acknowledge -all such points where the control currents are momentarily cut off, and the change of the car-carried apparatus, therefore, imposes a penalty by bringing the train to a stop, thus causing needless delays in spite of the engineers careful observance ofthe wayside signals and acknowledgement of their unfavorable indications.

With the above and other considerations in mind, it is proposed in accordance with the present invention to provide a system of continuous train control in which an automatic restrictive control due to the absence of control currents in short sections of the track rails is avoided and, more specifically it is proposed to provide a system-of this type incorporating a simplified distance element device for preventing the initiation of an automatic brake application until the vehicle has traveled a predetermined distance under unfavorable control influences, such predetermined distance being in excess of the longest of such sections ordinarily encountered in practice.

It is further proposed to provide a train control system of the type described in which a penalty is imposed upon the engineer if he fails to recognize an unfavorable signal indication and to perform a manual acknowledging act to evidence that he has seen and understood such unfavorable indication, and in which an automatic brake application is imposed if'a safe speed limit is exceeded While the train is traveling under favorable or unfavorable traffic conditions, such brake application being releasable after the vehicle speed has been reduced to a safe value.

Other objects, advantages and characteristic features of the invention will be pointed out or will become apparent as the description thereof progresses.

. In describing the invention in detail, reference will be made to the accompanying drawings in which Fig. 1 represents in a simplified and diagrammatic manner, a section of trackway equipped for automatic train control of the type embodying the present invention, together with the vehicle carried receiving and amplifying devices and the main car relay for use therewith;

Fig. 2 is a diagrammatic showing of the circuits and devices of the car-carried control apparatus;

Fig. 3 is a sectional view on an enlarged scale of the distance element relay used in connection-with this system; and

Fig. 4 is a sectional View taken on line 44 of Fig. 3 and viewed in the direction of the arrows.

Referring to Fig. 1, the track rails 1 have been shown divided into the usual blocks by the insulating joints 2, a complete block I and the ends of the two adjacent blocks H and J having been shown. As the signal and- V have been shown at the entrance end of each block with reference to the normal direction of traffic as indicated by the arrow, a showing of the well known operating devices for these signals being omitted as these devices and their operation form no part of the present invention and are well understood by those skilled in the art.

Direct or alternating track circuit current may be employed in connection with the present invention, and in the embodiment shown, alternating current is used, and alternating current track relays 3 of the well known type are connected across the track rails at the entrance end of each block. The track phase train control current, which is also track circuit current, is impressed across the track rails in series at the exit end of each block through a circuit including the secondary winding of the transformer 4 and the usual reactance coil 5, this circuit being obvious from the drawings. Alternating current of a suitable frequency is supplied to the primary winding of the transformer 4 through the pole changing contact fingers 6 and 7 from the transmission line 8 as clearly shown. The contact fingers 6 and "i are shown diagrammatically and it is to be understood that these fingers are operated in some suitable manner by the signal mechanism so that they will assume the position shown when the signal is in its clear or caution position, and will be dropped to their lower position, reversing theinstantaneous polarity of the track phase control current, when the signal is in its danger position.

The line phase or simplex train control current is continuously supplied to the track rails in multiple from the entrance end of each block to the point designated as b, which point is assumed to be located at such a distance from the exit end of the block that a train traveling at a medium speed, such as forty miles an hour, may be brought to a stop at the exit end of the block by a brake application initiated at this point. The circuit for supplying this constant line phase current may be traced as follows :from the secondary winding 9 of the transformer 10, wire 11,

balance resistance 12, the two track rails 1 in multiple, balance resistance 13 and wire 14 to the secondary winding 9 of the trans former 10. The line phase currentis supplied to that portion of the block between the point 6 and the exit end of the block under clear traffic conditions, through a circuit which may be traced as follows :-from the secondary winding 15 of the transformer 10 wire 16, balance resistance 13, the two track rails in multiple to the exit end of the block, balance resistance 17 wire 18, contact finger 19 and stationary contact 20 of the track relay 3 wires 21 and 22 movable signal contact 23 and stationary contact 24 and wire 25 to the secondary winding 15 of the transformer 10 The contact finger 23 is as sumed to be operated in accordance with the position of the wayside signal Z the circuit through this contact being closed when the signal is in its clear or caution position, and open When the signal is in its danger position.

From a study of the trackway circuits as described above, it is seen that when a train is located in a given block,say the block J, the track or loop phase current in this block behind the train is shunted from the track rails 1 by the wheels and axles of the train, causing the track relay 3 at the entrance end of this block to be de-energized and the sig nal Z to assume its danger position. This latter causes a reversal of the instantaneous polarity of the track phase current flowing in the track rails of the first block I in the rear, dueto the change of position of the contact fingers 6 and 7 and a consequent reversal of the contact finger 19 of the track relay 3 at the entrance end of the block I. The signal Z at the entrance end of the block I now assumes its caution position. The de-energization of the track relay 3 of the block J also causes the line phase current to be out off in that portion of the block 1 located between the point 6 and the exit end of this block, the circuit for this current being broken at the contact finger 19 of the track relay 3 and at the signal contact finger 23 Thus in an occupied or danger block, line phase current flows in the track rails for the entire blocklength and no track phase current flows in the track rails behind the train; in a caution block, track phase current of a reversed instantaneous polarity flows in the track rails of the entire block and line phase current flows in the track rails between the block entrance and the point I); and in a clear block, both track and line phase currents of'normal polarity flow in the track rails for the entire block length.

Referring now to the car-carried apparatus, a railway vehicle has been conventionally represented in the block H by the wheels and axles 26. This vehicle is provided with suitable receiving coils 27 and 28, which may or may not be provided with laminated iron cores. The receiving coil 27 is supported in inductive relation to one of the track rails at a point in advance of the leading axle of the veh cle, while the receiving coil 28 is supported in inductive relation to the other track rail at a point behind at least one of the vehicle axles, and preferably at a point in the rear of the locomotive tender. The receiving coils 27 and 28 are connected through suitable amplifiers 29 and 30, preferably of the audion tube type, to the windings 31 and 32 respectively of a suitable polyphase main car relay MR, these receiving circuits being obvious from the drawings. It may be pointed out that, although the flow of simplex, or line phase, current induces a potential in both of the receiving coils 27 and 28, this flow of current by itself does not produce a torque in the relay MR, because the relay MR is of such construction that currents displaced in phase are necessary in the windin thereof to produce operation. Considering now the effect the flow of line phase current of normal polarity in the rail under receiving coil 27 has when there is also a How of track phase current displaced in phase therewith, the presence of such line phase current may slightly increase or slightly decrease the electrical losses in apparatus 27293l depend ing upon whether the vector sum of these currents is greater or lesser than the track phase current itself. This slight change, if any, in the losses in the receiving apparatus does not materially change the torque produced by the relay, and as a practical proposition the induction of potentials in the coil 27 due to both line phase and track phase current does not have a detrimental eifectupon the operation of the relay.

Referring now more particularly to Fig. 2, the car-carried apparatus also includes two acknowledging stick relays, CS and DS. These relays are of the direct current type and are preferably made slow acting by some suitable means, such as the provision of copper sleeves around their cores to sustain the flux therein, the purpose of this slow acting feature being hereinafter described.

In the system of the present invention, a suitable manually operable contactor is provided by which certain circuits may be closed by the engineer in acknowledgment of the unfavorable indications of a wayside signal. This contactor is termed the acknowledging contactor, and is designated as a whole by the letters AC. As the completion of the circuits through the contactor AC acts in a manner hereinafter described to prevent the automatic actuation of the brakes, some suitable means must be provided to prevent the engineer from securing this acknowledging contaetor AG in its operated position. This feature may be ac complishedin any one of a number of suitable ways, but for the purpose of illustrating the invention, a simple contactor has been shown provided with a protection contact which is opened when the contactor is maintained operated for more than a pre determined time interval. The means of ob taining this result have been illustrated in an extremely simple form, and comprise a slidahly mounted rod normally held in the position shown by the spring 34 and provided with two movable contact members 35 and 36. A manually operable lever or handle 37 is pivotally mounted near the rod 33 and rests at its inner end upon a disc 33 rigidly connected to the rod so that:- an up ward movement of the handle 37 will cause the rod 33 to be depressed against the resistance of the spring 34, and will bring the movable contacts 35 and 36 into engagement with their stationary contacts. A second lever 38 is pivotally mounted near the top of the rod 33 and is forced by a spring 39 against the top of the rod as clearly shown, the spring 39 being slightly weaker than the spring 34 so that the rod 33 normally remains in the position shown. A dashpot 4:0 is secured by means of the link 41 to the lever 38 in such a manner that it will yieldingly resist the movement of this lever as produced by the spring 3 A movable protection contact finger 42 is so located that it will be moved to disengage its stationary contact 42 when the lever 38 is moved a predetermined distance by the spring 39 againstthe resistance of the dashpot 40. \Vhen the handle 37 is lifted to move the rod 33 to its lower posit-ion, the lever 38 is released, and the spring 39 moves this lever in a counter-clockwise direction about its pivot 43, this movement being very gradual because of the resistance offered by the dashpot 40. If the handle 37 and the rod 33 are not returned to their normal positions within a given period of time, the lever 38 engages the contact finger 42 and moves this finger to a position where it disengages its sta tionary contact 42 thus opening the protection circuit and causing a brake application as hereinafter described.

The vehicle brakes may be controlled 5 n any suitable manner and by any means adapted for this purpose, and for the purpose of illustrating the present invention a typical application valve AV of the type now common in train control practice has been shown in a simplified manner, the various connections between this valve AV and the regular air brake equipment being omitted for the sake of simplicity. As the operation of this application valve AV forms no part of the present invention and is well understood by those skilled in the art, a detailed description of its construction and operation will not be given, it being understood that main reservoir air pressure is supplied to the chamber 4A, flows through the leak port in the piston 46 and thus equalizes the air pressure on the opposite sides of this piston.

under normal conditions, the spring 47 acting to hold this piston in the normal lefthand position as shown. When the chamber 48 is quickly vented to atmosphere, the main reservoir pressure in the chamber lei moves the piston lt to the right and suitable valves are operated for initiating a brake application.

The chamber 4E8 is connected through the pipes 49 and 50 with an expansible element 51 this element being of such a construction that when air pressure is admitted thereto it expands to force the rod 52 to the position shown, and when the pressure is released from this element 51 the rod 52 is moved to the left, carrying with it the movable contact element 53 which engages suit-able stationary contacts to close circuits as hereinafter described.

The operation of the application valve AV and the expansion element 51 is controlled by a suitable electropneumatic valve EPV of the type now common in train control practice. This valve is connected by the pipe 54 to the pipes 49 and 50, comu'uuiicating with the chamber 48 of the application valve AV and with the expansion member 51 as clearly shown. The electro-pneumatic valve EPV as shown comprises an electro-magnet 55 normally energized to hold a valve portion 56 in its closed position, this valve portion 56 being biased to its open position by the spring 57.

In order that the progress of the vehicle may be limited to safe values under the various traflic conditions, a suitable car-carried speed responsive device is provided. This speed responsive device may take any suitable form, and as shown comprises a centrifuge Gr of the well known type which is preferably driven from the car wheels and which operates a movable pivoted contact arm 58 over suitable stationary contacts in a manner which is clearly evident from the representation in the drawing.

One particular feature of the invention comprises a simplified device for causing a delay in the initiation of an automatic brat: application until the vehicle has traveled a predetermined distance from the point at which unfavorable influences are first received. This device is termed a distance element relay, designated DB in Fig. 2, and is shown in detail on an enlarged scalein Fi 3 and l. Referring more particularly to Figs. 3 and at, the distance element relay coinprises a lower casing 60 in which are journaled the gears 61, 69. and S3 of a reduction gear train as clearly shown. The pinion (31 is secured to a shaft 64: which is driven in some suitable manner from the car wheels, being-preferably connected to the shaft of the centrifuge G as shown. The last gear (33 of the reduction gear train carries an extension 65 which engages a slotin a shaft 66 which is supported by a ball bearing (37 in the base 68 of the upper casing 69, the bearing 67 being secured to the base 68 by a. ring 70 and the screws 71. The shaft 66 is provided with an integral flange 72 at its upper end, and a friction disc 78, made of cork or other suitable material, is riveted to the upper surface of this flange 7 2.

The upper casing (39 carries an electromagnet E,'comprising the coil 74: and the hollow core 75. A plunger 76 is movably mounted in the core and is biased toward its lower or die-energized position by the spring 77 through a second plunger 7 8 and a ball bearing 7 E) as clearly shown. A small shaft- 80 is secured to the plunger 76 and extends downward in concentric relation to the shaft 66. A disc-shaped armature 81 is secured to the shaft 80 between the plunger 76 and an enlarged portion of the shaft 80 in such a manner that the energization of the coil 7% will cause this armature S1 to be attracted and to lift the shaft 80 to the position shown againstthe pressure of the spring 77. A contact operating lever 82 is pivotally secured to the electro-magnet frame 59 and extends across the lower end thereof as shown. .This lever is provided with an opening 83 through which the shaftVSO extends with ample clearance so that there is no contact between the shaft 80 and the lever 82. The opening 83 may be provided with an insulating bushing Set as shown.

Rotatably journaled on the shaft 80 be low the contact operating le er are a flange 85 and a heart-shaped cam 86, the nut 87 serving to retain these members on the shaft 80. The flange 85 is provided with a friction disc 88 of cork or other suitable material which is identical with the friction disc 7 3 on the flange 72. A cam follower lever 89 is provided being pivotally secured to the stud 9i) and carrying a roller 91 in the free end thereof, the roller being forced against the cam 86 by the spring 92 engaging the lever St). An upwardly extending portion 93 is provided on the cam follower lever, and engages the under surface of the contact operating lever 82. A depression 9-} is provided in the underside of the outer end of the contact operating lever 82, this depression being so placed that when the cam follower lever 89 has been forced to its extreme outer posi' tion by the cam 86, the contact operating lever 82 will be dropped a slight distance until the extending portion 93 engages the depression. 9d.

An insulating plate 95 is se rured to the electro-magnet frame 59 and carries a stationary contact 96 and a movable contact 97, the contact 97 being secured to a plunger 98 which is slidably mounted in a guiding frame 99, the plunger 98 with the contact 97 being biased to the open position by the spring 100. The contact operating lever 82, when in its normal position as shown, maintains the movable contact 97 in engagement with the stationary contact 96 by bearing against the lower end of the plunger 98, an insulated disc 101 being interposed between the plunger 98 and the lever 82 in order that the contacts may not be electrically connected with the framework of the mechanism.

In operation, when the coil 74 is de-energized, the armature 81 is released and the spring 77 forces the shaft 80, together With the flange 85 and the cam 86 downward, causing the friction discs 88 and 73 to securely clamp the cam 86 therebetween. The disc 73, being rotated through the gear train in accordance with the progress of the vehicle, imparts a slow rotation to the cam 86, the cam follower lever 89 is gradually forced to its extreme outer position and the contact operating lever 82 drops, permitting the spring 100 to open the contacts 90 and 97, thus breaking a control circuit which is hereinafter described. hen the coil 74 is reenergized, the armature 81 is attracted, carrying with it the lever 82, the flange 85 and the cam 86, thus releasing the cam 86 from the driving force imparted through the disc 73, and permitting the spring biased cam follower lever 89 to return the cam 86 to its normal position as shown in Fig. 3. WVhen the contact operating lever 82 is lifted by armature 81, the contacts 96 and 97 are closed and the control circuit is again completed.

0 pemtio n.

The apparatus as shown in the drawing has been illustrated in its normal operating condition, that is, the devices and circuits are in the positions which would be assumed with a train traveling under clear trafiic conditions and with all circuits properly energized. For simplicity in illustrating the circuits, the letters B and C have been used to represent the positive and negative terminals of a suitable source of electric energy, such as a storage battery.

Considering first the condition of the devices and circuits under clear traflic conditions, assume that the vehicle under consideration is proceeding in the block H with no train, broken rail or other hazard in the first two blocks I and J in advance. Under these conditions, track and line phase train control currents flow in the track rails of the block H and induce voltages in the receiving coils 27 and 28, which voltages are amplified by the amplifiers 29 and 30 and serve to energize the main relay MR in a normal direction, this normal energization being represented by the position of the contact fingers of this relay as shown in Fig. 2. Under these conditions, a circuit is completed for energizing the clear cab signal Gr. through a circuit including the contact finger 103 of the main relay MR, which circuit is obvious from the drawings. The coil 74 of the distance element relay DR is energized through a circuit which may be traced as folloWs:-from the battery terminal B, contact finger 104 and stationary contact of the main relay MR, wires 105 and 106, contact finger 42 and front contact 42 of the acknowledging contactor AC, wire 107, maximum speed stationary contact segment 108, movable contact segment 109 and stationary contact segment 110 of the centrifuge G, wire 111 and coil 74 of the distance element relay DR to the battery terminal C. Vith the coil 74 energized, the contacts 96 and 97 are maintained closed by the mechanism of the distance element relay in the manner described, and a circuit for energizing the electro-pneumatic valve EPV is completed, which circuit may be traced as follows z-from the battery terminal B, contacts 97 and 96 of the distance element relay DR, wire 112 and the Winding of the electro-pneuniatic valve EPV to the battery terminal C. Vith the electro-pneumatic valve energized, its valve member 56 is maintained closed and main reservoir air pressure is trapped in the chamber 48 of the application valve AV, thus permitting the spring 47 to force the piston 46 of the application valve to the left in which position no automatic brake application is imposed.

The vehicle under consideration may now proceed in the clear territory without restriction other than that imposed by the maximum speed contact segments 108 and 110 of the centrifuge G. If a maximum permissible speed, assumed to be seventy miles per hour, is exceeded, the centrifuge G moves the segment 107 to such a position that it disengages the stationary segments 108 and 110, and the energizing circuit for the coil 74 of the distance element relay DR is broken. The deenergization of the coil 74 initiates the rotation of the cam 86 and, after a predetermined distance of vehicle travel, the contacts 96 and 97 are opened, causing the deenergization of the electro-pneumatic valve EPV, the shifting of the piston 46 of the application valve AV, and a consequent automatic brake application. This brake application persists until the vehicle speed has been reduced to a value below the assumed maximum limit of seventy miles per hour, when the movable segment 109 of the centrifuge G again engages the contact segments 108 and 110, completing the energizing circuit for the coil 74 of the distance element relay, causing the contacts 96 and 97 to be closed, and thus reenergizing the electro-pneumatic valve EPV. WVith the electro-pnenmatic valve EPV again energized, the chamber 48 of the application valve AV is closed, and main reservoir pressure passes through the leak port 45 the engineer to release the brakes and proceed as before.

Considering now the operation of the control apparatus under caution traffic conchtions, assume that the train enters the block I when another vehicle is located in the block i J. Under these conditions track phase train control current of reverse polarity flows in the track rails of the block I and the wayside signal Z at the entrance end of the block I is in its caution position. Assume that the engineer is on the alert and observes and recognizes the caution indication of the signal Z and that he operates the acknowledging contactor AC just before the vehicle enters the block I. WVith the main relay MR still energized in a normal direction, a circuit is completed for energizing the caution stick relay CS, which circuit may be traced as follows:fro1n the battery terminal B, contact finger 114 and stationary contact of the main relay MR, wire 115, stationary contact 116, movable contact 36 and stationary contact 117 of the acknowledging contactor AC, wires 118 and 119 and the winding of the caution stick relay CS to the battery terminal C. As soon as the train enters the caution block and the track phase receiving coil 27 encounters the magnetic field set up by the track phase current of reverse polarity which flows in the track rails of this block, the main relay MB is energized in a reverse direction, swinging its contact fingers to the left, and the engineer then releases the acknowledging contactor AC, the relay CS being maintained energized through a stick circuit which may be traced as follows :from the battery terminal B, contact finger 104 and reverse stationary contact of the main relay MR, wires 120 and 121, front contact and contact finger 122 of the relay CS, wires 123 and 119 and the winding of the relay OS to the battery terminal G. Since the relay CS is slow acting as described above, the acknowledging contactor AC may be released before the main relay MR has swung to its reverse position to complete the stickcircuit just traced, the

relay CS maintaining its contact fingers closed for an interval of time after the deenergization of its windings. With the relay CS energized, a circuit is closed for energizing the distance element relay DR through .the medium speed contacts of the centrifuge Gr, which circuit may be traced as follows from the battery terminalB, contact finger 114 and reverse contact of the main relay MR,

wire 124, contact finger 125 and front contact of the relays GS, wires 126 and 127, me-

dium speed contact segment'128, movable segment 129 and medium speed segment 130 of the centrifuge Gr, wires 131 and 106, contact finger 42 and stationary contact 42 of the acknowledging contactor AC, wire 107, maximum speed contact segment 108, movable segment 109 and maximum speed segment 110 of the centrifuge Gr, wire 111 and the winding 74 of the distance element relay DR to the battery terminal C. A circuit for energizing the caution cab signal Y is completed through a circuit including the contact finger 103 and reverse stationary contact of the main relay MR, which circuit is obvious from the drawing.

If the train speed is in excess of the medium speed limit, assumed to be forty miles per hour, the circuit just traced is broken by the movable segment 129 of the centrifuge G, the distance element relay DR is cle-energized, causing the cle-energization of the electro-pneumatic valve EPV and a consequent automatic brake application as described above. This brake application persists until the train speed has been reduced to the medium speed limit, at which time the contact segment 129 again engages its stationary contact segments and the circuit for energizing the distance element relay BB is again completed, re-energizing the electro-pneumatic valve EPV and permitting the brakes to be released.

The train may now proceed through the caution block to the point 6 where the line phase or simplex current is cut off from the track rails as hereinbefore described. At this point, the main relay MB is cle-energized by reason of the absence of the line phase current, and if the engineer is alert and recognizes the point Z) which is preferably designated by some suitable wayside marker, he actuates the acknowledging contactor At just before the point 5 is passed and releases this contactor immediately after the train enters the section between the point Z) and the exit end of the block. The operation of the acknowledging contactor AC with the main relay in its reverse energized position completes a pick-up circuit for the danger stick relay DS, which circuit may be traced as follows :--from the battery terminal B. contact finger 132 and reverse stationary contact of the main relay MR, wires 133 and 134, stationary contact 135, movable contact and stationary contact 136 of the acknowledging contactor AC, wires 137 and 138 and the winding of the danger stick relay DS to the battery terminal C. As the vehicle enters the portion of the block located between the pointb and the exit end of the block and the acknowledging contactor AC is released, the danger stick relay DS is maintained energized through a stick circuit which maybe traced as follows :from the battery' terminal B, contact finger 132 and de-energized stationary contact of-the main relay MR. wire 139, front contact and contact finger 140 of the relay DS, wire 138 and the winding of the relay DS to the battery terminal C. lVith the relay DS energized, a circuit for energizing the danger cab signal R is completed through a circuitincluding the contact finger 141 and front contact of this relay, this circuit being obvious from the drawings, and the engineer is thus informed that he is operating in dangerous territory.

lVhen the main relay MR- movcs to its dcenergized position, the stick circuit for the relay CS, traced above, is broken. at the con tact linger 104 of the main relay MR. The relay CS is however maintained energized through an alternative stick circuit including the contact linger 142 of the relay Di which circuit is obvious from the drawings. The energization of the relay DS also maintains a low speed energizing circuit for the distance element relay DR which circuit may be traced as follows: from the battery terminal B, contact linger 143 and front contact of the relay DS, wire 144, stationary contact segment 145, movable segment 140 and stationary segment 147 of the centrifuge G, wire 127, contact segments 128, 129 and 1:30 of the centrifuge G, wires 131 and 106, contact tiu 42 and stationary contact 42 of the acknowledging contactor AU, wire 10?, contact segments 108, 107, and 110 of the centrifuge G, wire 111, and winding '74 of the distance element relay DR to the battery terminal C. The circuit just traced for energizing the winding of the distance element relay D1 is maintained closed by the movable contact segment 146 of the centrifuge G only provided the train speed is below the low speed limit, assumed to be twenty miles per hour, and if the vehicle is traveling at a speed in excess of this value when the point 7) is passed, an automatic brake application results, persisting until the speed has been reduced below the low value, when this brake application may be released, this brake application being initiated through the distance element relay DR and the clectro-pnenmatic valve EPV in the manner described above in connection with the entrance of a train into the caution block.

lYith the train speed reduced to a value below thi assumed low limit of twenty miles per hour, the engineer may release the brakes and proceed into the danger block w1thout further acknowledgment, the main relay remaining (lo-energized as the train travels in a danger block dueto the fact that no track phase control current flows in the rails of such danger block. No further restriction is imposed upon the engineer as the train proceeds into dangerous territory, it being assumed that the engineer is sutliciently alert and capable of bringing the train to a stop from the low speed which is enforced, his vigilance having been manifested by his proper operation of the acknowledging con-- tactor AC at the entrance to the caution block and upon encountering the point Z).

Considering now the operation of the control apparatus in the case in which the engineer is incapacitated or negligent to the extent that he fails to operate the acknowlec ging contactor upon the entrance of the train into a caution block, the main relay MR assnn'ies its reverse position as the caution block is entered and the circuit for energizing the distance element relay DR is broken when t he main relay contact finger 104 disengages its norn'ial stationary contact, this circuit having been traced above. Since the caution stick relay 7S has not been energized, no alternative energizing circuit for the distance element relay DR is completed, and after the vehicle has traveled a short dis tance, assumed to be about 150 feet, the dis tance element relay DR acts to de-energize the clectro-pnenmatic valve EPV, causing a brake application as hereinbefore described. This brake application persists until the train has been brought to a stop, the operation of the acknowledging cont-actor AG after the main relay MR has swung to its caution position being of. no avail to energize the relay US, as the pick-up circuit for this relay through the acknowledging contat-tor has been broken at the contact finger 114 and normal stationary contact of the main relay MR when the caution block was entered. The operation of the aclmowledging contactor AU vill of course complete the pick-up circuit for the danger stick relay DS, but no stick circuit for this relay can be completed with the main relay in its caution or reverse position, and as for reasons hereinafter described the acknowledging contactor can not be maintained in its operated position without imposing a brake application, the engineer may not set up the low speed limit to prevent the train being brought to a stop.'

The automatic brake application as a result of the failure of the engineer to acknowledge the caution signal causes the expansion element 51 of the application valve AV to contract, drawing the rod 52 and the movable contact 53 to the left and causing the contact lOO to engage its stationary contacts 148, 149

and 150. After the vehicle has been brought to a stop, the engineer may actuate the acknowledging contactor AC and thus energize the caution stick relay CS through a circuit which may be traced as follows :-from the battery terminal B, zero speed contact segment 151,1novablc segment 152 and zero speed segment 153 of the centrifuge G, wire 154, stationary contact 150, movable contact 53 and stationary contact 149, wire 155, stationary contact 116, movable contact 36 and stationary contact 117 of the acknowledging conactor AC, wires 11S and 119 and the winding of the relay CS'to the battery terminal C.

Once energized, the relay CS is maintained energized through astick circuit including the contact finger 11% of the main relay in its reverse position, which circuit has been traced above, and the train may proceed at the medium speed until the point 6 is reached.

A failure on the part of the engineer to acknowledge the existence of danger conditions upon reaching the point Z) results in the fact that the danger stick relay DS can not be energized by the subsequent operation of the acknowledging contactor AC, the pick-up circuit for this relay having been broken at the contact finger 132 and reverse stationary contact oi the main relay MR when the point Z) was passed. It the danger stick relay DS is not energized, the alternative stick circuit for the caution. stick relay GS is not completed,.

the relay GS is de-energized and, no circuit being made for energizing the distance element relay DR, an automatic brake application results which brings the vehicle to a stop. This brake application causes the expansion member 51 to contract and to move the con tact 53 into engagement with its stationary contacts, thus permitting the engineer to complete a pick-up circuit for the relays CS and DS through the zero speed contact of the cen trifuge G after the train has been brought to a stop. The pick-up circuit for the relay CS has been traced above and the pick-up circuit for the relay DS may be traced as fellows from the battery terminal B, zero speed contact segment 151, movable segment 152 and zero speed segment 153 of the centrifuge G, wire 15 1, stationary contact 150, movable con tact 53, and stationary contact 14-8, wires 156 and 134, stationary contact 135, movable contact 35 and stationary contact 136 of the acknowledging contactor AC, wires 13? and 138 and the winding of the relay DS to the battery terminal C. The relays DS and OS are now maintained energized through their stick circuits which have been traced above, and the vehicle may proceed in the danger territory under the restriction of the low speed contacts of the centrifuge G as hereinbetore described.

In Fig. 1, certain speed-distance curves have been shown representing the braking performances of trains in a caution block. The curve 157 represents the speed-distance performance for the poorest braked train, that is, for the train which, by reason of its weight and braking equipment, is most dillicult to retard or stop, while the curve 158 represents the speed-distance performance of the best braked train in a caution block. The dotted line 159 represents the restrictive speed limits set up by the speed contacts of the centrifuge G as described above in connection with train operation in a caution block, these speed contacts enforcing an automatic brake application at all train speeds over the as sumed medium speed limit of forty miles per hour from the entrance end of the caution block to the pointb, and for all speeds over the assumed low limit of twenty miles per hour between the point 6 and the exit end of the block. The curve 157 swings upward when the train speed has been reduced below a permissive limit represented by the line 159, representing the release of the brakes which may be effected by the engineer provided he has properly acknowledged the caution sig nal upon entering the block. The dotted extension 160 of the curve 157 represents the train performance if no acknowledgment has been made, the train being brought to a stop before the brakes can be released. The curve 158 for the best braked train also shows the release which may be effected when the train speed has been reduced to a value below the medium and low limits, the dotted extension of this curve representing the train performance if no acknowledgment has been made.

If the engineer attempts to forestall an automatic brake application by maintaining his acknowledging contactor AG in its operated position, the spring 39 gradually moves the lever 38 against the opposition of the dashpot 40 and after a given time interval the protection contact finger 41 is moved out of engagement with its stationary contact 42 by the lever 38. This breaks the energizing circuit for the distance element relay DR, the contacts 41 and 42 being included in this energizing circuit under all conditions of control, and an automatic brake application is initiated after a given distance of vehicle travel, in the manner described above. The engineer is thus prevented from defeating the operation of the automatic equipment by permanently securing the acknowledging contactor in its operated position.

In applying the continuous method of influence transmission to the trackways of railway systems,,certain points are encountered at which it is difficult or impossible to maintain the continuity of flow of the alternating control currents in the track rails. This condition exists at switches, cross-overs, and like points, and the de-en ergized sections of trackway are usually termed dead sections. An automatic brake application as a result of the de-energization of the main relay MR at these points is prevented in the present invention by the operation of the distance element relay DR. When the main relay is de-energized, breaking the energizing circuit for the distance element relay DR, the cam 86 is rotated through a train of gears as described above and the contacts 96 and 97 in the energizing circuit for the electro-pneumatic valve EPV are opened only after the cam 86 has been rotated an amount corresponding to a predetermined distance of vehicle travel, assumed to be about 150 feet, which is arranged to be in excess of the longest dead section ordinarily encountered in practice. If the main relay MR is re-energized before the contacts 96 and 97 are opened, no brake application is initiated and the train may proceed without restriction. In this manner needless delays in train operation as a result of dead sections are avoided.

The several features of the present invention have been described in connection with a rather specific system of train control embodying certain specific devices and apparatus. For this reason it should be clearly understood that the invention, as set forth in the appended claims, is not limited to the specific disclosure used, and that many modifications, additions and changes might be made without departing from its scope.

What it is desired to be secured by Letters Patent is 1. In an automatic train control system, means for transmitting influences corresponding to trafiic conditions to a moving vehicle, car-carried control apparatus comprising a main relay energized in accordance with said influences to assume a clear or a caution position, a stick relay having a pick-up circuit and a stick circuit, said pick-up circuit iiicluding a manually operable circuit closer and a contact of said main relay closed in the clear position, and said stick circuit including a contact of said main relay closed in the caution position, a speed responsive device having contacts closed only when the vehicle is traveling at or below a medium speed, a normally energized distance element relay, acting when de-energized to open a circuit for initiating a brake application after the vehicle has traveled a predetermined distance from the point at which said relay was deenergized, and an energizing circuit for said distance element relay, said circuit including a contact of said main relay closed in the caution position, a front contact of said stick relay and said medium speed contacts of said speed responsive device.

2. In an automatic train control system, car-carried control apparatus comprising a normally energized device for initiating a brake application after a given distance of vehicle travel from the point at which said device is deenergized, means controlled in accordance with influences corresponding to trafiic conditions received from the trackway for maintaining said device energized under favorable traflic conditions, and a circuit for maintaining said device energized under unfavorable traflic conditions including a front contact'of a manually energizable stick relay and contacts controlled in accordance with the vehicle speed.

3. In an automatic train control system, car-carried apparatus comprising a device for causing an automatic brake application after the vehicle has traveled a predetermined distance from the point at which said device is initiated, and means for controlling the initiation of said device including a speed responsiilre device and a manually energizable stick re ay.

4. In an automatic train control system, car-carried control apparatus comprising a normally energized device acting when de-energized to initiate an automatic brake application after a predetermined distance of vehicle travel, a speed responsive means having contacts opened at high and at medium speeds, a main relay controlled in accordance with influences corresponding to traffic conditions received from the trackway, a circuit for maintaining said device energized when influences corresponding to favorable traffic conditions are being received includin a contact of said main relay and said hig speed contacts of said speed responsive means,'a stick relay, a circuit including a manually operable contactor for energizing said stick relay only when influences corresponding to favorable traffic conditions are being received and a stick circuit for said stick relay closed only when influences corresponding to unfavorable traflic conditions are being received, and a circuit for maintaining said device energized under unfavorable traffic conditions including a contact closed when said stick relay is energized and said medium speed contact of said speed responsive means, said circuits for maintaining said device energized including a contact opened if said manually operable contactor is maintained operated for more than a predetermined time lnterval.

5. In an automatic train control system, 100 car-carried control apparatus comprising automatic brake applying apparatus, a normally energized device acting when deenergizedto initiate said automatic brake applying apparatus after a predetermined distance of vehicle travel from the point at which said device is de-energized, a speed responsive means having a plurality of sets of contacts opened when the vehicle exceeds predetermined speed limits, a main relay controlled in accordance with influences corresponding to traflic conditions received from the trackway, a circuit for maintaining said normally energized device energized when influences corresponding to favorable traflic conditions are being received including a contact of said main relay and contacts of said speed responsive means opened at and above a predetermined high speed, a stick relay, a circuit including a manually operable contactor for energizing said stick relay only when influences corresponding to favorable trafiic conditions are being received and a stick circuit for said stick relay closed only when influ- I ences corresponding to unfavorable trafiic conditions are being received, a circuit for maintaining said normally energized device energized under unfavorable traflic conditions including a contact closed when said stick relay is energized and contacts of said 'means closed when the vehicle is not in motion and contacts associated with said automatic brake applying apparatus and closed only when an automatic brake application is in efiect.

6. In an automatic train control system, car-carried control apparatus comprising means for applying the vehicle brakes, a normally energized device acting to initiate said brake applying means after a predetermined distance of vehicle travel from the point at which said device is de-energiz'ed, a speed responsive device having contact-s opened at and above predetermined high and medium speeds, two stick relays acting when energized .to maintain'said normally energized device energized through said medium speed contacts and said low speed contacts of said speed responsive means respectively, a main relay energized in'accordance with influences corresponding to traffic conditions received from the'trackway, a manually operable circuit controller, circuits for energizing one of said stick relays if said manually operable circuit controller is operated while influences corresponding to a favorable traffic conditionsar-e being received, and for energizing theother of said stick relays if said manually operable circuit controller is operated while influences corresponding to'unfavon able traffic conditions are being received, and further circuits for energizing both of said relays if the speed responsive means is in itszero speed position and said brake ap plying means is initiated.

' 7.".In an automatic train control system of the type in which influences corresponding to traffic conditions are transmitted from the traokway to a moving vehicle, car-carried apparatus comprising a brake applying means,

a device for causing the initiation of said brake applying means after a predetermined distance of vehicle travel from the point at which said device is initiated, means for ini-' tiating said device at a given vehicle speed under favorable trafiic conditions, means for initiating said device at a lower vehicle speed under unfavorable traffic conditions unless a manually actuable contacting means is actuated before the change to unfavorable traiiic conditions, and means acting if said manually'actuable means is not actuated before said change to unfavorable traflic conditions for causing an operation of said device and of said brake applying means which may not be released until the vehicle is brought to a stop with a brake application in effect.

' 8. In an automatic train control system, a device for causing theinitiation of an automatic brake applying means after a predetermined distanceof vehicle travelfrom the point'at which said 'deviceis initiated com prising, a shaft driven in accordance with the motion of the vehicle and carrying a friction disc, an electro-magnet, a cam rotatably supported above said friction disc, means for forcing said cam into engagement with said friction disc when said electro-magnet is de energized and means engaging said cam for causing a pair of contacts to open after said cam has been turned a predetermined distance by said shaft.

9. In an automatic train control system, a car-carried device for breaking a circuit after a predetermined distance of vehicle travel from the point at which said device is initiated comprising, a shaft driven in accordance with the motion of the vehicle, a cam rotatably supported above said shaft, an electro-magnet, means for holding said cam out of engagement with said shaft when said electroniagnet is energized, means for clamping said cam in engagement with said shaft when said electro-magnet is de-energized, a cam follower, and electrical contacts opened by said cam follower after said cam has turned a predetermined distance.

10. In an automatic train control system, a car-carried device for causing a delay of a predetermined distance of vehicle travel in the initiation of an automatic brake application comprising, a normally energized electro-magnet having a hollow core and an armature, a shaft rotatably carried in said hollow core and supported by said armature, a cam rotatably mounted on said shaft, a spring for moving said shaft downward when said electro-magnet is de-energized, a driving shaft driven in accordance with the motion of the vehicle and mounted in axial alignment withand below said cam, means on said shafts for clamping said cam therebetween when said electro-magnet is de-energized, a cam follower and means for breakingan electrical circuit to initiate an automatic brake application after said cam has moved I said cam follower a predetermined amount.

11'. A-car-carried device for an automatic train control system for initiatinga brake application after a predetermined distance of vehicle travel comprising, an electro-mganet having a hollow core and a spring pressed plunger in said core, a shaft rotatably mounted in said core, a cam and a friction disc ro tatably carried by said shaft, an armature engaging said shaft, a driving shaft mounted in axial alignment with said first mentioned shaft and carrying a second friction disc, said driving shaft being driven in accordance with the motion of the vehicle, a pair of contacts mounted adjacent said electro-magnet and biased to their open position, a contact operating lever pivotally secured to said electromagnet and acting to maintain said contacts closed when in its upper position, and a cam follower having a portion thereof engaging and supporting said contact operating lever when said cam is in its normal position and releasing said lever when said cam is in its extreme run-down position, whereby when said electro-ina net is tie-energized said cam is engaged by said friction discs and rotated by said driving shaft to its extrememun down position, releasing said contact operating lever and opening said contacts.

12. A train control system comprising, a normally energized brake control device which if de-energized effects an application of the brakes of the vehicle, a speed responsive device which at all times reflects the speed at which the vehicle is moving, a normally inactive distance device controlled by said speed responsive device and rendered active if the speed of the vehicle is excessive and having contacts associated therewith which are opened when the vehicle has traveled a predetermined distance after said distance de vice has been rendered active, and a circuit for energizing said brake control device including a source of energy and said contacts in series.

13. In a train control system, a normally energized brake applying device initiated upon de-energization, a contact in the energizing circuit for said device biased to open position, a holding member normally holding said contact closed, a coil which when energized, holds said holding member in contact closing position, a biased finger normally retaining said holding member in contact closing position, normally disconnected drive means operated in accordance with the progress of the vehicle for driving, when connected, said linger to a position where it no longer retains said holding member, and means for connecting said drive means to said linger upon de-energization of said coil.

14. In a train control system, a normally energized brake applying device initiated upon de-energization, a contact in the energizing circuit for said device biased to open position, a holding member normally holding said contact closed, a coil which when energized, holds said holding member in contact closing position, a biased finger normally retaining said holding member in contact closing position, normally disconnected drive means operated in accordance With the progress of the vehicle for driving When connected, said finger to a position where it no longer retains said holding member, means for connecting said drive means to said finger upon de-energization of said coil, and detent means for retaining said finger in its non-holding position, regardless of said drive means, only so long as said coil is de-energized.

In testimony whereof I hereby aflix my sig nature.

WILIAM D. HAILES. 

